Those stands are almost totally pointless.
Firstly, your speakers should be level, any tilt has a dramatic effect on the sound. To prove this to yourself wedge something under either front or back of speakers, then see how a tilt effects sound.
The only time you would want a speaker tiled is if your keeping it at a lower then ear height, however you might as well set things up correct and get stands the correct height.
Also, it's not just about getting speakers to ear height. When you lift a speaker away from desk you get less resonance with the desk, and this also improves sound, your putting more 'space' around the speaker.
At the moment you have your speakers on the desk. Play some music, then place your hands flat on the desk, you'll feel the desk resonating, this is effecting your sound.
In contrast if I place my hands on my desk, there is no resonance (vibration) coming into the desk, this is due to 1) speakers lifted from desk 2) isolation foam. When you reduce this resonance the sound is much cleaner.
EDIT. Another way to understand why speaker height is important. Go and collect some books in your house, then stack the books up and place the speakers on them.
Then to understand why isolation is important. Go and find some packaging foam or bubble wrap, place this under the speaker and see what effect it makes.